Inertia retractor

ABSTRACT

A safety seatbelt retractor having an actuator which releases a spring-biased pawl to lock the retractor reel in response to certain belt motions.

United States Patent David P. Jones Detroit, Mich.

June 11, 1969 Sept. 14, 1971 I Allied Chemical Corporation New York,N.Y.

Inventor Appl. No. Filed Patented Assignee [56] References Cited UNlTEDSTATES PATENTS 3,4 l 2,952 11/1968 Wohlert et al. 242/l07.4 3,446,4545/1969 Kovacs et al.... 242/107.4 3,450,368 6/1969 Glauser et al242/l07.4

Primary Examiner-Stanley N. Gilreath Assistant Examiner-Werner H.Schroeder Attorneys-Jonathan Plaut and Marvin Bressler ABSTRACT: Asafety seatbelt retractor having an actuator which releases aspring-biased pawl to lock the retractor reel in response to certainbelt motions.

PATENTED SEPI 4m 3.604.655

sum 1 or 3 INVENTOR .DHVLD P. JONE INERTIA RETRACTOR BACKGROUND OF THEINVENTION I. Field of the Invention This invention relates to safetyseatbelt retractors, and more particularly to those retractors which arenormally unlocked when the belt is extended and coupled to the user, butautomatically locked in response to certain emergency conditions.

II. Description Of The Prior Art Emergency-locking seatbelt retractorsusually have a reel which is connected to the belt for retraction. Thereel is normally unlocked even though the belt is buckled about theuser, thereby allowing him to perform normal body motions within thevehicle. A locking device, connected to a suitable actuator for sensingcertain vehicle conditions, locks the retractor to prevent beltextension in response to such emergency conditions.

A common form of actuator employs an inertia member which is mounted onthe retractor reel in such a manner that it moves with the reel wheneverthe reel is rotated at a normal rate, however, should the reel berotated at an acceleration associated with the belt being suddenlyextended, as during a vehicular collision, the inertia member isdisplaced with respect to the reel. This displacement is employed toactuate the locking device.

A common form of locking device comprises a pair of circular ratchetscarried by the reel, and a pawl which is mounted on the retractorsupport for movement toward and away from a locking position in which itengages the ratchets to prevent reel rotation in the direction in whichthe belt is extended. Usually the connection between the reel and thepawl is such that the pawl is moved, in response to the displacement ofthe inertia member, by a connection to the reel. The reels motion isemployed to move the pawl. Since the pawl is actuated in response toconditions in which the reel is being rotted at a highly acceleratedrate, the pawl is moved toward its locking position with a substantialacceleration until it engages the ratchets to stop the reel. Thedisadvantage of such a connection is that unless carefully designed thepawl may be difficult to release.

SUMMARY OF THE INVENTION The broad purpose of the present invention isto provide an emergency locking retractor in which the locking pawl ismoved toward either its locking position or its release position inmotions which are independent of the reels motion. In the preferredembodiment, a spring connects the pawl to the retractor support. A dogand ratchet mechanism mounted on the reel supports the spring such thatthe pawl is urged toward either its locking position or its releaseposition depending upon the reels direction of rotation and the positionof an inertia actuator.

The pawl is normally in its release position in which it allows the reelto rotate in either direction. When the reel is rotated in the directionin which the belt is unwound at a rate sufficient to displace theinertia actuator, the dog responds by releasing the pawl for motiontoward its locking position by the spring. The dog then is responsive toreel rotation in the opposite, winding direction, in a manner in whichthe pawl is released for motion toward its release position under thesprings influence. Thus, although the pawls motion is initiated by theactuator, its rate of motion depends upon the spring's characteristics.

Still further objects and advantages of the present invention willbecome readily apparent to those skilled in the art to which theinvention pertains-upon reference to the following detailed description.

DESCRIPTION OF THE DRAWINGS The description refers to the accompanyingdrawings in which like reference characters refer to like partsthroughout the several views, and in which:

FIG. 1 is a perspective view showinga seatbelt retractor, illustratingthe preferred embodiment of the invention, mounted in the passengercompartment of a vehicle;

FIG. 2 is an enlarged elevational view of the preferred retractor withits cover removed;

FIG. 3 is an exploded view of the preferred retractor;

FIG. 4 is an enlarged elevational view showing the retractor lockingmeans;

FIG. 5 is a fragmentary view taken along lines 5-5 of FIG. 4;

FIG. 6 is an enlarged view showing the locking means in its releaseposition with certain components being shown in phantom; and

FIG. 7 is a view similar to FIG. 6 but showing the locking means in itslocking position.

DESCRIPTION OF THE PREFERRED EMBODIMENT Now referring to FIGS. 1 and 2,a preferred seatbelt retractor 10 is shown as mounted on the floor panelof a vehicle 12, adjacent a seat assembly 14. A cover 16 encloses theretractor l0, and has an opening for a safety seatbelt 18. Belt 18 canbe extended from the retractor l0 and connected to a suitable fitting(not shown) on the opposite side of the seat assembly 14, in the mannerwell known to those skilled in the art. The retractor 10 is employed toretract the belt 18 toward a wound-up position within the cover 16.

Now referring to FIGS. 3, 4 and 5, the retractor 10 includes the support20 which is bent to form a pair of parallel sides 22 and 24 and a base26. The base 26 has an opening 28 for receiving a fastener 30 whichsecures the support to the vehicle 12. A shaft 32 is rotatably mountedon the support sides 22 and 24 with its ends extending beyond both ofthe sides. A spiral spring 34 is mounted on one end of the shaft 32which has a slot 36 for receiving the inner end of the spring.

A housing 38, mounted on the support side 22, encloses the spring 34 andhas a slot 40 for receiving the outer end of the spring in such a mannerthat the spring biases the shaft 32 toward rotation in the direction inwhich the belt 18 is retracted. However, the spring 34 allows the shaft32 to be rotated in the opposite direction as the belt 18 is extended.

The belt 18 is connected to the shaft 32 and wound about a reel 42. Reel42 is composed of a pair of circular ratchets 44 and 46 which areconnected together by a sleeve 48. The distance between the ratchets 44and 46 is sufficient to accommodate the width of the belt 18. Theratchet 44 is fixedly connected to the shaft 32 so that the reel and theshaft rotate together.

The belt is connected to the shaft by being passed through a slot 50,around the shaft 32, out of the slot and then being stitched to itselfto form a permanent loop. A pair of plastic washers 52 are mounted onthe shaft 32 between the ratchets 44-and 46 and their respective supportsides to provide a sliding engagement between the reel and the supportas the reel is rotated to extend or retract the belt.

A pawl 54 is mounted in a pair of openings 56 and 58 formed in supportsides 22 and 24 respectively. The pawl 54, which functions as a lockingmember, is movable between a lower release position, as illustrated inFIG. 6 in which it allows the reel to be rotated in either direction,and a raised, locking position in which it engages the ratchets 44 and46 to prevent rotation of the reel in its unwinding direction, asillustrated in FIG. 7. The means for controlling the motion of the pawl54 include a wheel 60 which is mounted on the shaft 32. A pin 62 locksthe wheel 60 to the shaft as shown in FIG. 5. The wheel 60 has a boss 64for slidably supporting an inertia member 66. The inertia member 66 hasa peripheral opening 68 for receiving a stop 70 carried by the wheel. Asetscrew 72 is mounted on the inertia member for adjusting therotational displacement between the inertia member 66 and the wheel 60.It is to be understood that the inertia member 66 functions as anactuator with its rotational displacement with respect to the wheel 60being employed as a means for actuating the motion of the pawl 54.

A dog 74, carried on a pin 76 of the wheel 60, is disposed in an opening78 of the inertia member. The dog 74 is pivotal between an outerposition illustrated in FIG. 6 and an inner position illustrated in FIG.7. A spring 80 biases the dog 74 toward its normal, outer position andthe inertia member 66 toward the position in which it is normallydisposed as the reel 42 is rotated either in its winding direction or inits unwinding direction at a relatively low rate of acceleration. Themass of the inertia member 66 is such that as the reel is rotated in theunwinding direction, or counterclockwise as viewed in FIGS. 6 and 7, thewheel 60 tends to be rotated in the counterclockwise direction withrespect to the inertia member. The spring 80 prevents relative rotationbetween the reel and the inertia member unless the reel is rotated withat least a predetermined acceleration in the unwinding direction. Thewheel 60 is then rotated in the counterclockwise direction with respectto the inertia member thereby pivoting the dog 74 toward its innerposition.

A ratchet 82 is mounted on the shaft 32 adjacent the inertia member 66,and has an arm 84. A pin 86 is carried on the arm 84 and supports apulley 88. A spring 90 has one end connected by a pin 92 to the supportside 24, and its opposite end connected by a pin 94 to the pawl 54. Thesprings midsection is mounted on the pulley 88. An elongated slide 96has one end connected to the pin 94 and its opposite end provided with aslot 98 for receiving the pin 86 of the ratchet arm.

In operation, whenever the dog 74 is in its outer position, the ratchet82 is free for rotation with respect to the shaft 32. In this positionof the dog, the spring 90 biases the pulley 88 to a position in whichthe pin 86 abuts the end of the slot 98 and thereby biases the pawl 54toward its release position. When the inertia member 66 is displacedwith respect to the wheel 60, in response to a sudden rotationalacceleration of the reel 42 in the unwinding direction, the dog 74 ispivoted toward the ratchet 82 as illustrated in FIG. 7.

When the dog 74 is engaged with ratchet 82, rotation of the shaft in theunwinding or counterclockwise direction rotates the ratchet 82 to raisepin 86 in the slot 98 of the slide thereby releasing pawl 54 for motiontoward its locking position. As the ratchet 82 is rotated by the reel,the pulley 88 is moved away from the pawl to extend the spring 90 whichbiases the pawl toward the ratchets 44 and 46 to stop further rotationof the reel in its unwinding direction.

When the pawl 54 is in its locking position, as shown in FIG. 7, reelrotation in the winding direction will cause the ratchet 82 and theinertia member 66 to rotate together until the pin 86 bottoms in theslot 98. This prevents further ratchet rotation so that further reelrotation disengages the dog 74 which then pivots toward its outerposition and returns the inertia member 66 toward its normal positionwith respect to the reel.

As the dog 74 becomes disengaged from ratchet 82, the

spring then returns the pawl 54 down toward its release position therebyreleasing the reel for rotation in its unwinding direction. Thus, boththe release motion as well as the locking motion of the pawl is actuatedby the reel. However, after each motion is actuated, the spring 90provides the moving force. g

It can further be seen that the slot 98 allows the reel to be rotated ina winding direction a certain distance before it is unlocked. Thus, whenthe reel is locked during an emergency in response to a sudden beltextension, it remains locked unless at least a predetermined amount ofthe belt is retracted thereby preventing unlocking before the conditionwhich produced the belt motion has passed.

Having described my invention, I claim:

1. In a vehicle safety seatbelt system, the combination comprising:

a support a reel rotatably mounted on the support;

a belt connected to the reel so as to be extended as the reel is rotatedin an unwinding direction, and to be retracted as the reel is rotated inthe opposite, winding direction;

an actuator mounted on the reel to respond to certain accelerated reelmotions in the unwindin direction; a locking member movably mounted on te support for motion between a locking position to prevent reel rotationin the unwinding direction and a second position to allow reel rotation;

bias means mounted on the support for urging the locking member towardsaid first and second positions; and

dog means pivotably disposed in an opening in the actuator forconnecting the locking member to the actuator, said dog meanscooperating with an intermediary member having mounted thereonpin-in-slot means connected to said locking member for automaticallymoving the locking member to its locking position in response to thereel being rotated with said accelerated motions, and automaticallymoving the locking member to its release position in response to reelrotation in the winding direction.

2. The combination as defined in claim 1, in which said actuatorincludes an inertia member mounted on the reel so as to be movablethereon in accordance with certain rotational accelerations of the reelon the support.

3. The combination as defined in claim 2, including means forcontrolling the rotational displacement of the actuator with respect tothe reel.

4. The combination as defined in claim 1, in which the actuator ismovable with respect to the locking member at such times as the lockingmember is disposed to prevent reel rotation in the unwinding direction.

1. In a vehicle safety seatbelt system, the combination comprising: asupport a reel rotatably mounted on the support; a belt connected to thereel so as to be extended as the reel is rotated in an unwindingdirection, and to be retracted as the reel is rotated in the opposite,winding direction; an actuator mounted on the reel to respond to certainaccelerated reel motions in the unwinding direction; a locking membermovably mounted on the support for motion between a locking position toprevent reel rotation in the unwinding direction and a second positionto allow reel rotation; bias means mounted on the support for urging thelocking member toward said first and second positions; and dog meanspivotably disposed in an opening in the actuator for connecting thelocking member to the actuator, said dog means cooperating with anintermediary member having mounted thereon pin-in-slot means connectedto said locking member for automatically moving the locking member toits locking position in response to the reel being rotated with saidaccelerated motions, and automatically moving the locking member to itsrelease position in response to reel rotation in the winding direction.2. The combination as defined in claim 1, in which said actuatorincludes an inertia member mounted on the reel so as to be movablethereon in accordance with certain rotational accelerations of the reelon the support.
 3. The combination as defined in claim 2, includingmeans for controlling the rotational displacement of the actuator withrespect to the reel.
 4. The combination as defined in claim 1, in whichthe actuator is movable with respect to the locking member at such timesas the locking member is disposed to prevent reel rotation in theunwinding direction.